The Washer,flat, cataloged under National Stock Number 5310-01-645-3644, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. Government technical data includes 8 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 5 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
Technical Specifications
Parameter
Value
NSN
5310-01-645-3644
Item Name
Washer,flat
FSC / FSG
5310 / 53 — Nuts and Washers
Status
ACTIVE
Overall Diameter
0.750 INCHES NOMINAL IN
Cross-Sectional Shape Style
RECTANGULAR
Surface Treatment
PASSIVATE OVERALL
Peripheral Shape Style
ROUND
Material
STEEL CORROSION RESISTING OVERALL
Center Hole Shape Style
ROUND
Hole Diameter
0.219 INCHES NOMINAL IN
Thickness
0.032 INCHES NOMINAL IN
Lifecycle & Compliance
Acquisition Status
ACTIVE
DEMIL Code
DEMIL A — No Demilitarization Required
Hazard
No hazard code in the DLA record (HMIC N)
Criticality Code
X
⇄Related Items5
Each row states its source: a government interchangeability/replacement code, or a possible match on a shared part number.
5310-01-685-1106140-009B17S26POSSIBLE MATCH
WASHER,FLAT
Possible match (shared part number)Bell Textron Inc
5310-01-686-4860140-009C25K48POSSIBLE MATCH
WASHER,FLAT
Possible match (shared part number)Bell Textron Inc
5310-01-686-5724140-009J17T64POSSIBLE MATCH
WASHER,FLAT
Possible match (shared part number)Bell Textron Inc
5310-01-686-6173140-009C13S32POSSIBLE MATCH
WASHER,FLAT
Possible match (shared part number)Bell Textron Inc
5310-01-686-6415140-009D17C48POSSIBLE MATCH
WASHER,FLAT
Possible match (shared part number)Bell Textron Inc
Cross-Reference Index
No manufacturer part numbers on file in the U.S. Government catalog.
Reference documents
Reference
Meaning
140-009
D/9Drawing number reference only
U.S. Government activity
140-009B14S48
3/2Design control — primary reference
U.S. Government activity
Related Parts
5310-01-685-1106POSSIBLE MATCH
WASHER,FLAT
140-009B17S26
5310-01-686-4860POSSIBLE MATCH
WASHER,FLAT
140-009C25K48
5310-01-686-5724POSSIBLE MATCH
WASHER,FLAT
140-009J17T64
5310-01-686-6173POSSIBLE MATCH
WASHER,FLAT
140-009C13S32
5310-01-686-6415POSSIBLE MATCH
WASHER,FLAT
140-009D17C48
Frequently Asked Questions
What is NSN 5310-01-645-3644?
NSN 5310-01-645-3644 is a Washer,flat, classified under FSC 5310, Nuts and Washers. Status: active.
What NSN replaces 5310-01-645-3644?
5 possible matches (shared part number, not a government interchangeability claim): 5310-01-685-1106, 5310-01-686-4860, 5310-01-686-5724. Verify interchangeability with system specifications before substitution.
What are the specifications of 5310-01-645-3644?
Key specifications for 5310-01-645-3644: Overall Diameter: 0.750 INCHES NOMINAL IN; Cross-Sectional Shape Style: RECTANGULAR; Surface Treatment: PASSIVATE OVERALL; Peripheral Shape Style: ROUND. 8 specifications are documented in the U.S. Government catalog.
Is NSN 5310-01-645-3644 hazardous material?
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
Sources
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
✓ Data cited from the U.S. Government catalog; commercial cross-references from OEM and certified industry sources.